Objective: To explore the correlation between the attachment type of lateral pterygoid muscle (LPM) and the position of temporomandibular joint (TMJ) disc in patients with temporomandibular disorders (TMD) by using wireless amplified magnetic resonance imaging detector (WAND) coupled with conventional head and neck joint coil for high resolution imaging of TMJ. Methods: Eighty-five patients with TMD diagnosed by oral and maxillofacial surgeons of Guizhou Provincial People's Hospital from October 2019 to January 2022 were collected. A total of 160 TMJ were included. There were 16 males and 69 females, aged (32.7±14.2) years. All patients were scanned with open, closed oblique sagittal and coronal WAND coupled head and neck coils with bilateral TMJ. Based on TMJ and LPM high resolution imaging, to explore the correlation between LPM attachment types and the position of TMJ disc in TMD patients, and to evaluate the potential clinical value of LPM attachment types in TMD patients. χ² test and Pearson correlation analysis were used to evaluate the correlation between LPM attachment type and TMJ disc location. Results: There were three types of LPM attachment: type Ⅰ in 51 cases [31.9% (51/160)], type Ⅱ in 77 cases [48.1% (77/160)] and type Ⅲ in 32 cases [20.0% (32/160)]. There was a significant correlation between the type of LPM attachment and the position of articular disc (χ²=28.20, P=0.002, r=0.776). There was no statistical significance between the type of LPM attachment and the reversible displacement of articular disc (χ²=0.24, P=0.887, r=0.825). Conclusions: There is a correlation between the attachment type of LPM and the position of the disc in TMD patients. WNAD coupled with conventional head and neck joint coil TMJ high resolution scan can provide reliable imaging evidence for TMD patients in evaluating the type of LPM attachment and the location of disc.
Male ; Female ; Humans ; Temporomandibular Joint Disc/pathology* ; Pterygoid Muscles/pathology* ; Joint Dislocations ; Temporomandibular Joint Disorders/diagnostic imaging* ; Magnetic Resonance Imaging/methods* ; Temporomandibular Joint/pathology*

OBJECTIVETo study the methodological techniques in measuring the severity of temporomandibulr disorders (TMD) and in evaluating the effectiveness of therapies in clinic.

METHODSBoth Fricton's Craniomandibular Index (CMI) and Helkimo's Clinical Dysfunction Index were calculated from 60 TMD patients. Inter-rater reliability was tested to assess the consistency in use between different examiners. Fricton's CMI was used to assess the clinical improvement after accepting a treatment in 21 TMD patients diagnosed as acute disk displacement without reduction.

RESULTSCorrelation Coefficient for inter-rater reliability in two groups was 0.879 and 0.939 respectively for Fricton's CMI and 0.744 and 0.838 for Helkimo Clinical Dysfunction Index. Fricton's TMJ dysfunction index was decreased from 0.337 to 0.021 (P < 0.001) and Fricton's CMI was decreased from 0.185 to 0.011 (P < 0.001) after the treatment in 21 TMD patients with disk displacement without reduction.

CONCLUSIONSTo avoid using subjective and descriptive report in assessment of the severity of TMD and the effectiveness of therapies, Fricton's CMI is recommended as an objective criteria which is simple in clinical use, and ease in scoring.

Adolescent ; Adult ; Child ; Female ; Humans ; Male ; Middle Aged ; Severity of Illness Index ; Temporomandibular Joint ; pathology ; Temporomandibular Joint Disorders ; pathology ; Temporomandibular Joint Dysfunction Syndrome ; pathology

OBJECTIVES: This study aimed to use modified articular disc anchorage in treating old irreducible temporomandibular joint (TMJ) disc displacement with perforation and rupture, as well as to explore its efficacy. METHODS: A total of 31 patients (34 sides) with 47 TMJ disc perforations who underwent surgical treatment in the Affiliated Stomatolo-gical Hospital of Nanchang University from January 2018 to December 2021 were selected. According to the location of disc perforation, it has five types: posterior disc perforation (typeⅠ), anterior disc perforation (typeⅡ), lateral disc perforation (type Ⅲ), composite disc perforation, and destruction disc perforation. The modified methods of disc anchoring were divided into two types according to the location of the perforation. TypesⅠandⅢ disc perforation were trea-ted by posterior anchoring method. For posterior ancho-ring, a screw was implanted into the posterolateral side of the condylar neck, and the disc was fixed on the screw by horizontal mattress suture. TypeⅡdisc perforation and compo-site disc perforation combined typeⅡperforation were treated by anterior and posterior double-anchoring method. For anterior anchoring, anchor screws or holes were placed at the anterior edge of the condylar neck, and horizontal mattress suture was performed at the posterior edge of the anterior perforation with an anchor wire. The articular disc was then fixed on the anchor screws or holes. For the posterior anchoring method, it was the same as the previous one. Paired t test was used to analyze the visual analog scale (VAS), maximum interincisal opening (MIO), and TMJ disorder index (CMI) of the patient before surgery and 1, 3, and 6 months after surgery. Disk-condyle position relationship by magnetic resonance imaging and postoperative quality of life in postoperative were analyzed. RESULTS: The incidence of perforation was 41.2% (14/34) in typeⅠ, 11.8% (4/34) in typeⅡ, 8.8% (3/34) in typeⅢ, 29.4% (10/34) in composite type, and 8.8% (3/34) in destruction type. The VAS, MIO, and CMI at 3, 6 months after operation significantly improved compared with those before operation (P<0.05). The effective reduction rate of disc was 96.77% (30/31). The quality of life at 6 months after surgery was 47.22±2.13, and the rate of excellent evaluation was 96.4% (27/28). CONCLUSIONS Modified articular disc anchorage achieves a good curative effect for treating temporomandibular joint disc perforation and rupture. Nevertheless, its long-term effect requires further observation.
Humans ; Temporomandibular Joint Disc/surgery* ; Quality of Life ; Joint Dislocations/surgery* ; Temporomandibular Joint Disorders/surgery* ; Magnetic Resonance Imaging/methods* ; Temporomandibular Joint/pathology* ; Mandibular Condyle

OBJECTIVETo study the chondrocyte apoptosis in rabbit temporomandibular joint after anterior disc displacement.

METHODSExperimental anterior disc displacement was induced surgically in 20 Japanese rabbits without opening their temporomandibular joint bursas. Histopathologic and apoptotic (TUNEL) analysis was used to evaluate the changes in articular cartilage, disc and synovium.

RESULTSCondyle chondrocyte showed apoptosis most obviously at 1 or 2 weeks after surgery, and apoptotic cells concentrated in proliferative zone and hypertrophic zone. 4 or 6 weeks after surgery, the joint went into a remodelling period.

CONCLUSIONSChondrocyte apoptosis in temporomandibular joint will be activated after anterior disc displacement, which initiates the remodelling in temporomandibular joint.

Animals ; Apoptosis ; Chondrocytes ; pathology ; In Situ Nick-End Labeling ; Joint Dislocations ; physiopathology ; Rabbits ; Temporomandibular Joint ; physiopathology ; Temporomandibular Joint Disc ; physiopathology

The temporomandibular joint (TMJ) is frequently imaged in head and neck computed tomography (CT) and magnetic resonance imaging (MRI) studies. Depending on the indication for the study, an abnormality of the TMJ may be an incidental finding. These findings encompass both intra- and extra-articular disorders. They may also be related to local, regional or systemic conditions. Familiarity with these findings along with pertinent clinical information helps narrow the list of differential diagnoses. While definitive diagnosis may not be immediately apparent, a systematic approach contributes to improved discussions between clinicians and radiologists and better patient management.
Humans ; Temporomandibular Joint Disorders/pathology* ; Incidental Findings ; Temporomandibular Joint/pathology* ; Tomography, X-Ray Computed ; Magnetic Resonance Imaging

OBJECTIVETo study the adaptive alterations of elastic fibers in the bilaminar zone (BZ) of rabbit temporomandibular joint (TMJ) following disc displacement.

METHODSTwenty-eight Japanese white rabbits were used in this study. The right temporomandibular joints of 20 of 28 rabbits were subjected to the surgical procedure of anterior disc displacement (ADD). Four rabbits in the surgical group were sacrificed at 2, 4, 6, 8 and 12 weeks after operation. Their temporomandibular joints were studied histochemically.

RESULTSElastic fibers were reduced in number and ran irregularly in the superior lamina of BZ from ADD rabbits. The jungly elastic fibers (EFs) could still be seen at 2 weeks after operation. At 4 weeks, the number of EFs decreased significantly; EFs lost their jungly arrangement and were shaped like rough dots, of which the arrangement and the lengths were different. Six weeks after operation, many EFs were replaced by distorted, uneven, non-oriented fine EFs, distributed unevenly and some thick or fine EFs that ran irregularly. The number of EFs decreased further and their arrangement was more deranged at 8 weeks. At 10 and 12 weeks, EFs in the superior lamina of BZ were similar to those at 8 weeks.

CONCLUSIONOur results show that EFs lost their function as well as their distribution and arrangement after disc displacement.

Adaptation, Physiological ; Animals ; Behavior, Animal ; Elastic Tissue ; pathology ; Extracellular Matrix ; pathology ; Joint Dislocations ; pathology ; Rabbits ; Temporomandibular Joint Disc ; pathology ; Temporomandibular Joint Disorders ; pathology

OBJECTIVETo investigate whether the gradually induced disordered occlusion can induce degenerative changes in rabbit TMJ.

METHODS27 male New Zealand Rabbits, age of 5 months were divided equally and randomly into three groups: Group A: One premolar in upper dentition at one side and another premolar in lower dentition at the other side were pulled to move medially to the anterior intrinsic space by an orthodontic string to cause the corresponding premolars not to occlude with the opposites coincidently. Group B: the sham-operating controls, all animals were treated similar to those in Group A but without pulling. At the age of 6, 7 and 8 months, three rabbits of each group were killed by deeply anaesthetizing and bilateral condyles of TMJs were excised, sectioned and stained with HE.

RESULTSThere was no significant histological difference in condylar cartilage between Group B and C. The cartilage of TMJs condyle in Group A was found with significant degenerative changes that increased with age. The thickness of cartilage of anterior and intermediate part of condyles decreased, the disturbance of continuation of hypertrophic layer appeared and part of hypertrophic layer was locally replaced by fibrous tissue. While the thickness of cartilage of posterior part of condyle increased obviously with a significant increase of the proportion of immature chondrocytes.

CONCLUSIONThe gradually induced disorder occlusion may lead to degenerative changes in rabbit condyle.

Animals ; Cartilage, Articular ; pathology ; Male ; Malocclusion ; pathology ; Mandibular Condyle ; pathology ; Rabbits ; Random Allocation ; Temporomandibular Joint ; pathology

Cartilage and giant cell-related neoplastic lesions originating in the temporomandibular joint region have similar clinical, imaging and pathological manifestations, making the diagnosis of these disorders challenging to varying degrees. Diagnostic findings can influence treatment procedures and a definitive pathological diagnosis is important for the prognosis of these conditions. In this article, we discuss the pathological diagnosis and differentiation of four benign cartilage and giant cell related tumors and tumor-like lesions that occur in the temporomandibular joint, namely synovial chondromatosis, tumoral calcium pyrophosphate deposition disease, pigmented villonodular synovitis and chondroblastoma, taking into account their clinical features and histological manifestations, with a view to providing a basis for clinical management.
Humans ; Temporomandibular Joint/pathology* ; Chondromatosis, Synovial/pathology* ; Synovitis, Pigmented Villonodular/pathology* ; Giant Cells/pathology* ; Cartilage

OBJECTIVETo study the adaptive alteration in bilaminar zone of rabbits' temporomandibular joint following disc displacement.

METHODSTwenty-six Japanese white rabbits were used in this study. Among these rabbits,6 were used as controls. The right discs of other 20 rabbits were displaced anteriorly by operation. Four of these rabbits were killedatn 1, 2, 4, 6 and 8 weeks respectively after surgery. The TMJS were studied by HE staining, Alcin bluen staining and in situ detection of type II collagen mRNA expression.

RESULTSThere appeared cartilage metaplasia after one week following disc displacement. Typical chondrocytes could be found in the bilaminar zone. The new chondrocytes expressed type II collagen.

CONCLUSIONSThe bilaminar zone of TMJ will be remodeled following disc displacement and become a disc-like tissue to function as a disc.

Animals ; Collagen Type II ; biosynthesis ; genetics ; Female ; Joint Dislocations ; metabolism ; Male ; RNA, Messenger ; biosynthesis ; Rabbits ; Temporomandibular Joint Disc ; metabolism ; pathology ; Temporomandibular Joint Disorders ; metabolism ; pathology

OBJECTIVETo study the characteristics of apoptosis in the condyles of osteoarthritic temporomandibular joints, and investigate its role in the pathogenesis of the disease.

METHODSTemporomandibular joint osteoarthrosis model of rabbits was created by partial resection of joint disc. The animal models were sacrificed in the 15th day, the 1st month, the 2nd month, the 3rd month, the 4th month, the 5th month, and the 6th month chronologically. Then the pathological condyles were sectioned and detected with TUNEL method to investigate the apoptosis within the tissue.

RESULTSIn the reactive repairing state of osteoarthrosis, the apoptosis cells mainly located in the superficial fibrous layer of articular cartilage. With the remodeling of articular cartilage and bone, the apoptosis cells gradually appeared in the proliferating layer, especially in the "clusters of chondrocytes". Accompanied with the severe damage and loss of articular cartilage, the phenomena of apoptosis decreased in the lower zone of cartilage and increased in the hypertrophic and calcified zone.

CONCLUSIONThere were abundant phenomena of apoptosis within the condylar cartilage of osteoarthritic temporomandibular joint. Abnormal proliferation and abundant apoptosis would disturb the regulation mechanism in the cartilage matrix and lead to the osteoarthrosis.

Animals ; Apoptosis ; Male ; Mandibular Condyle ; pathology ; Osteoarthritis ; pathology ; Rabbits ; Temporomandibular Joint Disorders ; pathology